What is PHP?

‘PHP: Hypertext Preprocessor’, widely known as PHP, is a scripting language that runs on web servers. It is mostly used to create dynamic pages that interact with databases, like social networks and online forums.

A PHP file has a .php extension and can contain PHP, HTML, JavaScript, and CSS code.

When a user requests a page containing a PHP file, the site’s server processes and outputs it as plain HTML. This way, the source code is safe from prying eyes.

What is PHP used for?

In web development, PHP can perform various tasks:

• Interact with MySQL databases – it can access databases and generate content on the fly, like displaying recommended products to different users in an eCommerce site.
• Keep users logged in – information about a user’s login credentials and logged-in status is stored in PHP cookies and sessions.
• User authentication – you can write PHP code that runs usernames and passwords against your database.

Outside of the web context, PHP has several uses.

For instance, PHP scripts can be executed locally as long as a PHP parser is installed on your computer. Use a PHP script to process text files, clean out directories, or modify local files.

Creating desktop applications is also possible with PHP. However, it requires PHP extensions like PHP-GTK and WXPHP.

Why use PHP?

Using PHP presents several advantages:

• It’s free open-source software, and there are lots of forums and tutorials available online.
• PHP is a common server-side scripting language, so you can use it in many projects.
• There’s no need to install a PHP parser as most web servers support PHP, making it cost-effective.
• PHP works well with HTML, and it’s comparatively easier to learn than other programming languages.
• It works with all database software like MySQL, Oracle, and Sybase.

How PHP works to display dynamic web pages

Dynamic pages are those that change based on the request made. For example, a blog article page changes as users add more comments, and the homepage of your Facebook account is always updated with the latest posts.

Here’s how PHP displays dynamic web pages:

1. A user accesses a website, and the browser sends the request to the web server.
2. The server looks through the directory files and sends .php files to the PHP interpreter.
3. The PHP interpreter parses the PHP code and executes it by generating HTML code.
4. The server receives the output and sends it back to the browser, which then displays the web page.